The wor proposed is as follows: 1. Gene freguency analysis of Bogoda semispecies, D. pseudoobscura, D. persimilis and D. miranda at 50 different loci by electrophoretic analysis of proteins made by different genes. 2. Associations of genes with third chromosome gene arrangements of D. pseudoobscura and with inversions of different chrmosomes in D. robusta. 3. Electrophoretic analysis of ribosomal proteins of D. pseudoobscura. 4. Selection experiments on alleles of xanthine dehydrogenase locus in D. pseudoobscura. 5. Studies on kinetics and activities of allozymes in Drosphila.